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Full text of "Monsieur Auzout's Speculations of the Changes, Likely to be Discovered in the Earth and Moon, by Their Respective Inhabitants"

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who fhall feethefe GlaflTes 3 how they couldbetruiy wrought 
to fuch a Figure 5 with fuch a Cavityi & yet more, when they 
fhall hear the Author undertake to excavate other fuch Eye- 
Glafies to above two inches , and 0bje8-glajfes of five inches 
Diameter. He hath likewife already begun his ObjcS-glaJfes 
for the mentioned two Ocularonc$> of the fame Figureof 
about two inches Diameter, which are to be left all open, yet 
without caufing any colours. Of all which 'tishop&l, that 
fhortly a fuller and more particular accompt will be given. 

Monfteur Auzout's Speculations of the Changes Ji\efy 
to he dif covered in the Earth and Moon > by their 
refpe$ive Inhabitants, 

This Xnquifitive Philosopher in a letter of hisjately written 
tohiscorrefpondentin London^ takes cccaftcn to difcourfe 
of his confiderations concerning thofe Changes, mentioned 
in the Title % as folio wes h 

I have ( faith he ) fometimes thought upon the changes, 
which 'tis likely y the fuppofed Inhabitants of the Moon 
might difcover in our Earth > to fee 5 whither reciprocally I 
could obferve any fuch in the Moon. For example 3 me* 
thinks D that the Earth would to the people of the Moen ap- 
pear to have a different face in the feveral feafonsofthe 
year; and to have another appearancein Winter D when 
there is almoft nothing green in a very great part of the 
Earth 3 when there are Countries all covered with fnow 3 
others > all covered with water 5 others s all obfeured with 
Cloud* , and that for many weeks together : ^nothnm 
Sprmg % when the Forrefts and Fields are green. Another in 
Summer 5 when whole Fields areyellov/ &c. Me thinks^ 
I fay 5 that thefe changes are confiderable enough in the force 
of the reflexions of Light to be obferved 5 fince we fee fo 
many differences of Lights in the Moon. We have River? 
confiderable enough to be feen 3 aid they enter far enough 



into tin Land , and have a bredth Capable to be obferved. 
There are Fluxes in certain places,that reach into large Goun- 
tricSjenough to make there fome apparent changed in fome 
of our Seas there float fometimcs fuch bulky maffes of Ice 5 
that are far greater,tbanthe Objedb, which we areaflured., 
we can fee in the Moon. Again, we cut down whole Forrefts, 
anddraip Marifhe», of an extent large enough to caufe a 
notable alteration: And men have made fuch works, as 
h#ve produced Changes great enough to be perceived. In 
many places alfo are Vulcans # that feem big enough to be 
diftinguiflh't , efpecially in the fhadow : And when Fire 
lights upon Forrefts of great extent, or upon Towns, it 
can hardly be doubted, but thefe Luminous Objefts would 
appear cither in an Ecclipfe of the Earth, or when fuch part * 
of the Earth are not illuminated by the Sun, But yet,Iknow 
no man , who hath obferved fuch things in the Moon ; and 
one may be rationally aflured that no Vulcans arc there, or 
or that none of them burn at this time* This it is Cfo he 
goes on ) which all Curious men that have good Tele/cope/^ 
ought well to attend 5 and I doubt not, but, if we had a ve- 
ry particular Map of the Moon&s I had defigned to make one 
\vith a Topography , as it were , of all the confiderable places 
Therein, that We or our Pofterity would find fome changes 
in Her* And if the Mapps of the Moon of Hevelms^Divini^nd 
Riccioli&KZ exaftj can fay,that I have feen there fome place* 
confiderable enough, where theyym parts that are clear , 
whereas J there fee dark_oncs. Tis true that if there be Sear 
in the Moon , it can hardly fall out otherwlfe 5 than it doth 
upon our Earth, where Alluviums are made in fome places, 
and the Sea gains upon the Land in others. I fay $ if thofc 
Spots we fee in the Moon^ areScas, as mofi: believe them to 
be 5 whereas I have many reafons , that make me doubt > 
whether theybefo* of which I (hall fpeak el fe where. And 
Ihavefometimes thought, whether it might not be, that all 
the Seas of the Moon * if there muft be Seas :, were on the 
fide of the other Hemfpbere^ and that for this caufe it might 
be that the Mm* turnsnot upon its Axis > asour Earthy 

R. 2 wherein 


Wherein the Lands and Seas are , as it vvere 5 bal!anced:Tlut 
thence alfo may proceed the non-appearance of any Clouds 
raifed there, or of any Vapors confiderable enough to be 
feen , as there are raifed upon this Earth 5 and that this ab- 
fence of Vapors is perhaps the caufe 5 that no Crcpttfcleis 
there > as it fecms there is none, my felfe at leaftnot ha* 
ving hitherto been able to difcerne any qpark thereof: For , 
me thinks, it is not to be doubted, but that the reputed Ci- 
tizens of the Moon might fee our Crepvfcle, fince we fee, that 
the fame is without comparifon ftronger, than the Light af- 
forded us by the Moon^ even when (he is /#//} for D a little 
after Sun- fet, when we receive no more thej?r/? Light of the 
Sun , the sky is far clearer , than it is in thefaifeft night of 
the/*// Moon. Mean while , (ince we fee Jn the Moon^htn 
the is increafing or decreafing , the Light, fhereceives-from 
the Earth, we cannot doubt ^ but that the People of the 
Moon (hould likewife fee in the Earth that Light > where- 
with the Moon illuminates it 5 with perhaps the difference* 
there is betwixt their bignefs. Much rather therefore Ihould 
they fee the Light of the Grepufcle , being , as we have faid , 
incomparably greater . In the mean time we fee not any 
faint Light beyond the StBwn ofthc Light , whiclris every 
where almoft cqualy ftrong , and we there diftinguifii no% 
thing atall, not 10 much that cleereft part > which is called 
AriftArchvd>QrtVorph)Htes , aslhavsoften tryed 5 although 
one may there fee the Light, which the Earth fends thither, 
which is fometimes fo ftrong , that in the M on*s decre&fe I 
have often diJiwQly feen all the parts of the Mw#,that were 
not enlightned by the Sun, together with the difference ofthc 
clear parts, and the Spots , fo far as to be able todifcern 
them all. The shaddoves alfo of all the Cavities of rhe Moon 
feem to be ftronger , than they would be, if there were a 
SccohdlAght. For, although a far off 3 the (haddows of our 
Bodies, environed with Light, feem to Us almoft dark} 
yet they do * not To appear fo much 9 as the Shaddows of the 
Moon doe 5 and thofc that arc upon the Edge of the 'self ion , 


(123 J 

fhould not appfear in the like manner. But, I will determine 
nothing of any of thefe things* When I (hall hereafter have 
made more frequent Obfervatiqns of the Moon with my 
great Telefcopes, in convenient time, I fhall then perhaps learn 
more of: it, than I know at prefent, at leaft it will excite the 
CtmoHs to endeavor to make the like Obfervations; and it 
may be> others^ that I have not thought of* 

The Inpance of the fame Perfon to Mr. Hook, for 
commnnicatinghk Contrivance of making^with a 
Glafs of a Sphere of to or 40 foot diameter^ Te- 
lefcopc drawing federal hundred foot\and his of 
fer of recompensing thdt Secret with another Reach- 
ing To weafure with ^Telefcope the Diftances 
of Obje&s upon the Earth. 

Jd TXumh* 4. Of thefe Papers^ png. 6j. Mr. Hook, had inti- 
mated 3 tkat he would fhortly difcover a way of his, with a 
TlMQ-convexQlattc of a Sphere of 20. or 40* feet Diameter^ 
without Vtines^ and truly wrought of that figure^ to make 
a Telefcope^ that with a fingle Eye-glafs fliould draw 300, 
400, yea I0O0 feet, without at all altering the Convexity ; 
Monfieur Auzout returns this confederation, and offer upon 
it, which follows : 

To perform (faith he) with a leffcr OfyeB ~gl*fi the effeft of 
a great Tclefcope , we muft find out a way to make 
fuch an OhyU'glafs to receive as many Rayes as one will, 
without their being fenfibly diftant from one another S to 
the end, that by applying to it a flronget Eye*glafs, there 
may beftill Beams enough to fee the Objed, and to oblite- 
rate the fmall fpecks and imperfeftions of the Eyc-glafs. 
And if Mr. #00^ hath this Invention, I efteem it one of the 
greatefi^ that can be found in the matter of Telcfcopes; if 
he pleafe to impart it to us, we (hall be obliged to him ; 2nd 

I. with,